Oscillator generator



July 2, 1929. w SCHAFFER 1,719,521

OSCILLATOR GENERATOR 7 Filed July 15, 1925 v anvemboz WaZ 1 497150774 ffer as, his exam/" 22 y 4 an Patented July 2, 1929.

UNITED STATES PATENT OFFICE.

WALTER sonar-ran, or BERLIN, GERMANY, Assreivoa T GEsnLLscnAr'r mm DRKHTLOSE TELEGRAPHIE M, B. I L, 013 BERLIN, GERMANY, A. CORPORATION OF GERMANY.

OSCILLATOR GENERATOR.

Application filed July 15, 1925, Serial No. 43,700, and in Germany July 25, 1924.

Owing to various causes, it has heretofore been found diflicult to produce very high frequency oscillations by means of transmitting apparatus employing vacuum tubes. Aside from the fact that the effect of internal-capacities is increased as the tubes are made of greater power, another dlfficulty arises in maintaining generated oscillations evenly at that when primarily anddirectly producing fore to obviate the difficulties above referred short waves, the capacitance ofthe circuit which determines the frequency. must be made extremely low; When variations of the position and dimensions of the antenna occur, or very-small changes in capacitance are caused, such'as by a person approaching the apparatus, or by the movement of conductivebodies in the neighborhood of the apparatus, the effect of small percentage changesof capacitance which govern the frequency andthe length of wave assumes relatively large proportions.

An ob'ect of the present invention is there to so that. the effects thereof are diminished at the outset. This is'accomplished by first Droducing'a wave of greater length or of low frequency instead of a short wave of high frequency, and then from the anode circuit of the generator-tube which produces I the primary long wave oscillations there are obtained harmonic waves which are modulated according to the modulation in said primary tube. In the generation of short waves producedby harmonics of a longer j wave, as here proposed, the wave length is dependant upon the use of a much larger condenser; in consequence of which capacitative influences, regardless of their nature or source, react primarily upon the fundamental wave. and consequently the effect on the harmonics will be considerably less.

The harmonic waves thus obtained can be supplied directly to the aerial from which they are to be radiated, or to any other kind of utilization, or transfer, or amplification circuit.

As an example of various arrangements to produce the above results reference may be had to the accompanying drawingformmg a part of this specification, in which i 1 Fig. 1 is a diagrammatic View illustrating the general principle of the'invention;

Fig. 2 is a similar diagrammatic View illustrating a modified form thereof; and

Fig. 3 is a similar diagrammatic view illuszrating another modified form of the invenlon. I Referring to the drawings, the numeral 1 lndicatesthe primary generator tube which is connected with an oscillatin circuit 2 which may be tuned to a wave length, for

example, 'of 500 meters Inthe anode 01" plate circuit of the tube 1 is connectedthe oscillatory circuit 3 which may be tuned, for

example, to the tenth harmonic, that is to say, a 50 meter wave length. The anode'circult is coupled to the oscillatory circuit 3, as indicated in said Fig. 1, it being assumed, as

before, pointed out, that the alternating cur- 1 rent in the: anode circuit is-not truly sinusoidal buthas been'distorted or modulated -which is placed in the anode or plate circuit of the tube 1 and tuned to the higher harmonics. This may be further promoted by the aid of auxiliary means, such as by a relatively high negative direct current potential applied to the grid circuit. The energy of the high frequency current thus obtained is, generally' speaking, but a comparatively small fraction of the energy which the primary tube is capable of producing, becausepart of this energy is used up in the oscillatory circuit 2. It will be apparent that in coupling the aerial circuit with the oscillatory circuit 3, the" coils may be so arranged and the capacitance so adjusted as to produce the optimum coupling. If increased ower is desired, it will be necessary to ampli y the harmonics obtained, as aboveset forth. This can be accomplished most simply by conducting the current of the harmonic oscillations to a high frequency amplifying tube, the output of which is applied to the aerial circuit.

Referring now to Fig. 2, the arrangement therein illustrated is one in which the high frequency oscillations pass through and are amplified in the same tube in which the oscillations of low frequency are generated. The numeral l indicates the generator tube and 5. themainoscillatory circuit for the low frequency oscillations. 6 is the oscillatory circuit from which the harmonic oscillations quency oscillations are amplified and the former-thussupplied .to the oscillatory circuit 6 from which-point they are transmitted -to theantenna. r

In Fig. 3 an arrangement is illustrated in which the tube 9 is the main generator for the low frequencyoscillations which are supplied to the oscillatory circuit 10, in which vtheflow frequency oscillations take place. The high frequency oscillatory circuit is indicated at 11 .and is coupled at 12' with the high frequency amplifying tube 13, the output .ofwhich supplies the oscillatory circuit 14 with high frequency amplified oscll-lations. This circuit is coupled with the antenna (311- ,cuiit through a variable; coupling as indicated at 16. Theoscillatory circuit 1.4 is also coulpled as indicated at 1'5. withthe grid of the main generating tube 9,,whichcircuit is also coupled with the lowfreqnency oscillatory circuit 10 as indicated at- 17. A second stage of amplification is thereby produced and the energy thus amplified is then conducted bywayofthecircnit t1, coupling 12, tube 13and oscillatory circuit 15 to theantenna circuit 16. Having thus described these forms. of my invention what I claim and desireto protect by Letters Patent is:

1. Apparatus for the generation and radiation of short electric waves of constant frequency comprising, a main generating tube, a ,parallelresonant oscillatory circuitof comparatively low frequency connected therewith the anode current in which is modulated ac-- cording to the desired signals to: be trans nntted, a second parallel resonantoscillatory circuit connected directly in series with the lowfrequency oscillation circuithof said tube and: tuned to a harmonic of tl-leoscillations produced in the first named oscillatory circuit", an. antenna circuit and means for eoupling said harmoniooscillatory circuit with the antenna circuit.

2. App'aratusfor the'generatmn and. radia- 1310111 of short electric waves ofconstant frequency comprising, a main generating tube, an oscillatory circuit of comparatively low frequency coupled therewith the anode current in which is modulated according to the desired signals to be transmitted, a second oscillatory circuit connected with said tube and tuned to a harmonic of the oscillations produced in the first named oscillatory circuit, means for coupling said low frequency oscillatory circuit with said tube regeneratively, whereby the low frequency oscillations are selfgenerated, an antenna circuit, and means for coupling said harmonic oscillatory circuit with theantenna circuit.

3. Apparatus for the generation and radiation of short electric waves of constant frequency comprising, a main generating tube, an oscillatory circuit of comparatively low frequency connected therewith the anodecurrent in which is modulated according to the desired signals to be transmitted, a second oscillatory circuitconnected with said tube and tuned to aharmonic of the oscillations produced in the first named oscillatory circuit, means for regeneratively coupling said low frequency oscillatory circuit tube to generate low frequency oscillations, means to regeneratively couple the harmonic oscillatory circuit to amplify the harmonic, an antenna circuit, and means for coupling said harmonic oscillatory circuit with the antenna circuit.

45. Apparatus for the generationandradiation of short electric' waves of constant frequency comprising, a main generating tube, an oscillatory circuit of comparatively low frequency connected therewith the anode current" in which is modulated according to the desired signals to be transmitted, a second oscillatory circuit connected with said tube and tuned to a harmonic of the oscillations pro duced in the first named oscillatory circuit, a tube for amplifying said harmonic oscillations, a third oscillatory circuit connected with said amplifying tube, means for coupling said third circuitwith said low fre= quency oscillation cir'cuitand with the grid of' said maiin generating tube, an antenna circuit, and means for coupling said third oscillatory circuit with the antenna circuit.

5. 'A tubevgenerator for the production of short waves at constant frequency, comprisingatube oscillator for generating a longer wave, a parallel resonant circuit tuned to a harmonic frequency connected in series with the anode circuit of said tube,'and means to utilize the higherfrequency. l i

6. A tube transmitter accord-ingto claim 5, in which the harmonic frequency taken from the anode circuit is fed back to the generating tube for the purpose of amplifying the waveofharmonic frequency;

7. A tube transmitteraccording'to claim 5 having a separate amplifier tube to which the harmonic frequency taken from the anodecircuit, is first fed, and a feed-back connection circuit of the oscillator tube, and means coupling said resonant circuit to the rid circuit 10 of the oscillator in order to ampfify the de-, sired harmonic.

Signed at Berlin, Germany, this 27th day of June, 1925. I

WALTER SOHAFFER. 

